SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    143574, 154235, 157361, 133193, 132858, 
    132112, 121316, 166649, 161383, 156616, 
    169021, 155568, 129545, 143889, 157865, 
    158465, 119733, 157747, 135156, 141356, 
    170940, 153217, 141168, 139111, 152784, 
    127480, 165385, 161916, 175582, 151286, 
    118370, 131161
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00634

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.0564324,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_descriptions",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["product_id", "lang_code"],
          "loops": 1,
          "rows": 32,
          "cost": 0.0564324,
          "filtered": 100,
          "attached_condition": "cscart_product_descriptions.product_id in (143574,154235,157361,133193,132858,132112,121316,166649,161383,156616,169021,155568,129545,143889,157865,158465,119733,157747,135156,141356,170940,153217,141168,139111,152784,127480,165385,161916,175582,151286,118370,131161) and cscart_product_descriptions.lang_code = 'en'"
        }
      }
    ]
  }
}